Semiconductor integrated circuit devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductor layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon.
Over the past several decades, the semiconductor integrated circuit industry has experienced rapid growth. Technological advances in semiconductor materials and design have produced increasingly smaller and more complex circuits. These material and design advances have been made possible as the technologies related to processing and manufacturing have also undergone technical advances.
Many of the technological advances in semiconductors have occurred in the field of image sensing. A backside illuminated (BSI) image sensor is one of the types of image sensors used in integrated circuits. However, although existing backside illuminated image sensors have generally been adequate for their intended purposes, as device scaling-down continues, they have not been entirely satisfactory in all respects.